Fig. 4.

Female HCC resistance is PRL-dependent and regulated above c-Myc. (A) Absence of sex bias in preneoplastic foci and HCC in Alb-Myc(tg) mice with constitutive hepatic c-Myc expression. (B) Immunohistochemical confirmation of cytoplasmic and nuclear c-Myc overexpression (diaminobenzidine; brown) in transgenic mice of both sexes compared with WT controls (magnification, 400×). (C) Increased HCC incidence (Upper) and multiplicity (Lower) in PRL-deficient mice relative to WT controls. (D) DEN-initiated Prl^−/− mice have greater local (arrowheads) and vascular (arrows) tumor invasion than sex-matched WT controls (magnification, 200×). Data are expressed as mean ± SEM (n = 9–10 per sex per treatment protocol), *P < 0.05, one-way ANOVA with Tukey posttest.